I keep being nagged to upgrade, but I see the most prominent change is to do with Sierra. I’m still using Mavericks - should I bother with this upgrade?
If one isn’t on Apple’s treadmill, and they don’t need to sync with any iDevices, I would say there is less reason to upgrade, true. Some bugs have been fixed, so that would be worth looking through to make sure nothing impacting you is in the way. Most of serious bugs that have been fixed since then are all thanks to issues introduced by Apple though, issues that wouldn’t exist if you’re sticking with an older system.
I would turn off the automatic update check (or nag as you put) though—there is a security flaw in those older checkers that could lead to your system being compromised on unencrypted WiFi.
I’ve turned off the automatic check - thanks for the warning.
The list of bugs fixed is lengthy but I don’t see any showstopppers for me there. On the other hand, would I find any problems upgrading to current, or would an in-between version (2.6 or 2.7) suit me better, or just do nothing?
(I suppose one possibility might be to save v2.5 to an external drive, upgrade, then revert to 2.5 if I find problems?)
You can rename your current Scrivener to “Scrivener 2.5”, and then manually download the latest version and install it if you want to try it out. Do note that the scrivener project format changed after 2.5, so projects created in or upgraded to version 2.8 won’t open in Scrivener 2.5.
A change of file format complicates things a bit.
If I did what you suggest, then rename 2.8 to “Scrivener New” and the older one back to “Scrivener”, I could run both (though not simultaneously), and create a new project in 2.8 to see if everything was ok.
The main problem as I see it is that this could cause big problems with the Preferences and Application Support files, right?
You might be right. Renaming the new version to experiment with it seems like a sound strategy.
I routinely run multiple versions of Scrivener for support purposes. I sometimes get confused because a particular function I’m looking for is in a different place, but Scrivener seems to handle preferences and such just fine.
As noted, though, 2.8.1 uses a different project format. Scrivener will make a backup when it converts, but of course that backup won’t include any changes you make post-conversion.
Katherine
So running 2.5 for my regular projects and 2.8 for a test project then back to 2.5 again, won’t cause any problems you can think of?
I have about six or so different versions installed, from 1.5 to stuff that doesn’t even exist yet. 
The main issue I’ve run into is that OS X Services can get a little confused when you have more than one copy of a program installed. If you never use those, all you really want to do is make to sure to “Get Info” on any of your Scrivener projects and set the “Open With” default to 2.5 so you don’t accidentally load projects in 2.8 (nothing would be harmed since you have to confirm upgrading the project format, but it’s annoying).
Thanks Amber. I’ll certainly do that for “Scrivener” (which will be 2.5 and most of my projects). 2.8 (“Scrivener New”) I will launch specifically and it should open the test project by default, or else it will be in the File/Recent menu.